Effect Of Temperature On Egg Diapause Of Migratory Locust

The oriental migratory locust Locusta migratoria manilensis (Meyen) is an important agricultural pest. A large number of studies have shown that temperature influences locust egg diapause. Whether eggs are in diapause period or not by winter is an important factor which influences their propagation next year. However, there is no systematic research about the relationship between temperature and locust egg diapause. We studied the influence of temperature and accumulated temperature on egg diapause overwintering. The results are as follows:Diapause existed in migratory locust. With the increasing of effective accumulative temperature, development duration of the oriental migratory locust shortened and diapause rate decreased. When the effective accumulative temperature was over840.0DD, all locust eggs hatched. Diapause rate (D) and DD before overwintering (Y) were negative correlation, D=-0.719Y+82.75, R2=0.774. When Y was over115.1DD, all eggs hatched. Effective accumulative temperature above27℃had the most significant impact on diapause rate. The function of Intrinsic rate of increase (rm) and effective accumulative temperature(t) was:rm=-1E-06t2+0.001t-0.482, R2=0.956. The optimal effective accumulated temperature interval of the oriental migratory locust was545-705DD.For locust eggs just entering winter, higher incubation temperature could increase hatching rate. Function relationship of diapause rate (y) and negative accumulated temperature (x) was y=-0.1551n(|x|)+1.136, R2=0.970. Termination of diapause required negative1523.9DD. Diapause rate (D) of26,28,30,32℃and incubation temperature (T) is negative linear correlation, D=-7.855T+251.1, R2=0.99. The upper temperature limit of entering diapause was19.2℃and the minimum temperature of breaking diapause was32.0℃.After Illumina Hiseq2000sequencing, we obtained more than three hundred million reads in two libraries.32,493CDS blasted against protein databases.10,176Unigenes were predicted with ESTScan, with15,201unigenes aligned to Nt database,31,888unigenes aligned to NR database,25,547unigenes aligned to Swiss-Prot database.22,766unigenes were aligned to259known metabolism and signal pathways, with15,667unigenes annotated by COG,15,837unigenes annotated by GO.36,765unigenes of total100,490unigenes were annotated by these protein databases, which were highly conserved and function-known. To screen for differentially expressed genes in non-diapause eggs and diapause eggs, the expression of62,241unigenes in100,490unigenes were different. Statistical data showed that37,516unigenes were up-regulated and24,725unigenes were down-regulated. Egg diapause of migratory locust is associated with heat shock protein.